An m77t file extension is related to the GEODAS MGD77T Marine Geophysical Data Exchange Format.
M77T file extension - GEODAS MGD77T data
What is m77t file? How to open m77t files?
File type specification:
The m77t file extension is associated with the Marine Geophysical Data Exchange Format an exchange format for marine geophysical data (bathymetry, magnetics, and gravity).
The m77t file stores marine geophysical data used by GEODAS software.
The GEODAS software is obsolete.
This m77t file type entry was marked as obsolete and no longer supported file format.
This type of file is no longer actively used and is most likely obsolete. This is typically the case for system files in old operating systems, file types from long discontinued software, or previous versions of certain file types (like documents, projects etc.) that were replaced in higher versions of their original programs.